In both military and non-military organizations, materials capable of marking the landing or impact site of a projectile after firing from a weapon are commonly employed to assure that the projectile has been delivered to its desired target site.
Indeed, military personnel shoot a variety of weapons and grenade launchers as part of their training. The training is often conducted throughout various military bases and test ranges. During such training, it is particularly important for the users to be able to accurately determine where the fired rounds landed so that adjustments required to hit a target are practiced. In some instances trainees view the impact area with the naked eye. However, training can also include the use of night vision goggles (NVG's), which intensify low light levels, or thermal weapons sights, which detect infrared (IR) signals. Effective training rounds must be capable of marking the landing or impact site of a projectile by creating a signal that can be detected from a distance by an observer during both the day and night, using any of the above methods.
Traditionally, training rounds may contain colored smoke, pyrotechnic compositions or chemiluminescent reaction components to provide signals on impact. While colored smoke can provide a visible signal during the daytime, it is quite difficult to detect at night.
Pyrotechnic compositions can provide signals in the visible region and several IR regions, but have undesirable characteristics when used for training rounds. For instance, in any training scenario, there is some incidence of “dud” rounds which do not function properly on impact. The malfunction of “dud” rounds can be caused in several ways including malfunctioning of the ammunition hardware and of the fuse device. Pyrotechnic training rounds must incorporate a fuse device which ensures that the round will not accidentally detonate if dropped or improperly used. Fuses are typically complex devices with some level of function failure. As a result, pyrotechnic training rounds may not function on impact due to a fuse failure. Any pyrotechnic-containing rounds which do not detonate on impact result in an Unexploded Ordnance (UXO) hazard on the range. Clearing the range of these UXO hazards involves the use of highly trained specialists and consequently, is dangerous and costly.
Moreover, some of the materials incorporated within pyrotechnic training rounds are hazardous and thus pose an environmental concern when utilized. Rainwater leaching of these materials results in pollution of the range soil and groundwater where such training rounds are employed.
Yet another undesirable characteristic of pyrotechnic training rounds is their tendency to start range fires when deployed during dry or arid conditions.
Chemiluminescent rounds utilize materials which emit light when mixed on impact. While they can provide acceptable signatures at night, the light is not bright enough to be clearly visible during the day. In addition, these materials do not emit in the midwave or longwave IR, so they are not visible on thermal weapons sights. Another shortcoming of chemiluminescent rounds is that the duration is relatively long, which can be a problem when training using multiple burst rounds.